Some of the millions of oyster shells that Americans are used to throw away are now rebuilding the coast where they came from. The Coalition to Restore Coastal Louisiana, a non-profit advocacy organisation, collects more than 1,300 tonnes of oyster shells from dozens of restaurants.They end up in wire containers used to build an 800-metre-long barrier reef along the Biloxi Marsh, a part of the Mississippi River Delta that has seen significant erosion. Al Jazeera's Jonathan Martin reports from Buras.